Secret Agent P, AKA Perry the Platypus, is on a mission: he must foil the evil Dr. Doofenshmi­rtz’s plan to save the day in “Phineas and Ferb: The Best Live Tour Ever” at the St. George Theater on April 17 and 18.

Musical madness and tons of fun abound when the cartoon characters come to life on the big stage. The escapade is so huge and awesome that even Candace can’t help but join in the hijinks. It’s the ultimate end of summer vacation, so come seize the day, ’cause Phineas and Ferb are gonna do it all.

“Phineas and Ferb: The Best Live Tour Ever” at the St. George Theater, [35 Hyatt St. in St. George, (718) 442-2900] April 17 and 18 at 7 pm. Tickets are $22.50–$82.50. For more info, visit www.stgeorgetheatre.com.